Bookmakers demoted Jonbon from Arkle Chase favouritism in response to his hard-fought success at Warwick.
Nicky Henderson's top novice was pushed out to 2-1 with most firms after he was given a real fright by sole rival Calico. The withdrawal of Haddex Des Obeaux, Jonbon's main opponent on the form book, appeared to give the 1-16 favourite a straightforward task.
But Calico, rated 23lb inferior, failed to read the script in the Grade 2 Virgin Bet Kingmaker Novices' Chase. A fluent leap at the fourth last fence carried him several lengths clear of the hot favourite, who set out to make the running.
